A computer-implemented method, system, apparatus, and non-transitory media is directed to providing a graphical user interface for insuring a default of debts specified in financial instruments. A computer system establishes a capital structure which includes an insuring debt related to an insured debt of a debtor based on an insured debt amount representing at least a proportion of the insured debt. A first loss class and a second loss class is allocated for an insuring trust. The capital structure is simulated, including a payment payable from the insuring debt to a first class holder in the first class, wherein the first class holder is entitled to the payment based on a debt to the first class holder of an insuring fund of the insuring trust. An user interface provides a simulation of the capital structure including an insuring scenario based on various alterable inputs.